Question

Calculate the molarity of the solution that results when 45.0 g of KOH is dissolved in enough water to make 250.0 ml of solution?

a. 2.24 mol/L
b. 0.312 mol/L
c. 3.21 mol/L
d. 0.180 mol/L
e. 45.0 mol/L

Answer 1

Answer:

The molarity of this KOH solutions 3.21 mol / L (option C is correct)

Explanation:

Step 1: Data given

Mass of KOH = 45.0 grams

Molar mass of KOH = 56.1 g/mol

Volume = 250.0 mL = 0.250 L

Step 2: Calculate moles KOH

Moles KOH = mass KOH / molar mass KOH

Moles KOH = 45.0 grams / 56.1 g/mol

Moles KOH = 0.802 moles

Step 3: Calculate molarity

Molarity KOH solution = moles KOH / volume water

Molarity KOH solution = 0.802 moles / 0.250 L

Molarity KOH solution = 3.21 mol / L

The molarity of this KOH solutions 3.21 mol / L (option C is correct)